The present invention is particularly directed to the unifelt type systems for drying papers. In such systems paper sheets such s fine paper or newsprint paper leaves the press while wet and in a relatively weak condition. The paper is dried by being conveyed over a series of drying cylinders. In one known arrangement felt support members are disposed on each side of the paper while it is being conveyed through the drying installation. A modification known as the unifelt system uses only a single fabric support member in the portion of the machine where paper is weakest, i.e., at its wet end. It has been found in practice that the provision of the support member is necessary only while the paper is being conveyed over the first six or eight drying cylinders at the wet end. Thereafter the paper may be conveyed by the conventional double felt arrangement.
The unifelt systems generally used encounter a process problem resulting in air traveling with the fabric support member. With conventional unifelt there is no outlet for the trapped air. As a result the paper sheet is caused to bulge, flutter and wrinkle. This problem is particularly acute at the wet end of the machine where the paper sheet is very weak and can readily break.